| 摘要 |
<p>Extended surfaces are formed by metallic fins in parallel and at right angles to tubes, which are interconnected by the fins. The fins are held in position by distance pieces which envelope the tube and are held in position by heat shrinkage or by a clip. The parallel strips are doubled, installed at right angles so that tightness and rigidity are increased while expansion clearances are allowed for in one direction only on each strip. Distance pieces may have a slit so that they can be moved along the tube and fastened in any selected position.</p> |
